Ember.js EmberArray indexOf() Method

Last Updated : 23 Dec, 2022

Ember.js is an open-source JavaScript framework used for developing large client-side web applications which is based on Model-View-Controller (MVC) architecture. Ember.js is one of the most widely used front-end application frameworks. It is made to speed up development and increase productivity. Currently, it is utilized by a large number of websites, including Square, Discourse, Groupon, Linked In, Live Nation, Twitch, and Chipotle.

The indexOf() method is used to find the index of a given object in the array.

Syntax:

indexOf( obj, startAt );

Parameters:

obj: It is the item whose index we have to find.
startAt: The index from where to start the search.

Returns: It returns the index or -1 if object is not present.

Installation Steps:

Step 1: To run the following examples you will need to have an ember project with you. To create one, you will need to install ember-cli first. Write the below code in the terminal:

npm install ember-cli

Step 2: Now you can create the project by typing in the following piece of code:

ember new <project-name> --lang en

To start the server, type:

ember serve

Example 1: Type the following code to generate the route for this example:

ember generate route Index1

app/routes/Index1.js

import Route from '@ember/routing/route'; 
  
export default class ListRoute extends Route { 
    list = ["apple", "grapes", "Banana",  
        "Tomato", "Onion", "Potato", "Garlic", 
        "Dosa", "Idali", "Samosa", "Orange"]; 
    temp; 
    idx; 
    model() { 
        return this.list; 
    } 
    setupController(controller, model) { 
        super.setupController(controller, model); 
        controller.set('list', this.list); 
        controller.set('temp', this.temp); 
        controller.set('idx', this.idx); 
    } 
}

app/controllers/Index1.js

import Ember from 'ember'; 
import { 
    clear, insertAt, indexOf, lastIndexOf, 
    includes 
} from '@ember/array'; 
  
export default Ember.Controller.extend({ 
    actions: { 
        selectattr(temp) { 
            this.set('temp', temp); 
        }, 
        checkIndex(data) { 
            let res = this.list.indexOf(data); 
            alert((res != -1) ? `Index of ${data} is 
            ${res}` : "List not contains item") 
        }, 
    }, 
});

app/templates/Index1.hbs

{{page-title "List"}} 
<h3>Here is a list of Items: </h3> 
<ul> 
    {{#each @model as |i|}} 
        <li>{{i}}</li> 
      {{/each}} 
</ul> 
<br /><br /> 
<br /> 
<div> 
    <label>Select Attribute: </label> 
      <select onchange={{action "selectattr"
      value="target.value"}}> 
    {{#each this.list as |attribute|}} 
        <option value={{attribute}}>{{attribute}}</option> 
    {{/each}} 
    </select> 
</div> 
<br /> 
<div> 
    <input 
        type="button"
        id="get-Index"
        value="Check Index"
        {{action "checkIndex" this.temp}} 
      /> 
</div> 
{{outlet}}

Output: Visit localhost:4200/Index1 to view the output

Ember.js EmberArray indexOf method

Example 2: Type the following code to generate the route for this example:

ember generate route Index2

app/routes/Index2.js

import Route from '@ember/routing/route'; 
  
export default class PartyRoute extends Route { 
    student = [ 
        'Rahul', 
        'Sam', 
        'Chitransh', 
        'Pankaj', 
        'Yogesh', 
        'Balit', 
        'Pokhraj', 
        'Gulshan', 
        'Sameer', 
        'Bhavesh', 
        'Rohan', 
        'Ranju', 
        'Manisha', 
        'Alok', 
        'Chitransh'
    ]; 
    item; 
    idx; 
    model() { 
        return this.student; 
    } 
    setupController(controller, model) { 
        super.setupController(controller, model); 
        controller.set('student', this.student); 
        controller.set('item', this.item); 
        controller.set('idx', this.idx); 
    } 
}

app/controllers/Index2.js

import Ember from 'ember'; 
import { 
    insertAt, indexOf, lastIndexOf, 
    includes 
} from '@ember/array'; 
  
export default Ember.Controller.extend({ 
    actions: { 
        insertItem(item, idx) { 
            this.student.insertAt(idx - 1, item); 
        }, 
        getRank(item) { 
            let res = this.student.indexOf(item); 
            alert(`Rank of ${item} : ${res + 1} `); 
        }, 
    }, 
}); 

app/templates/Index2.hbs

{{page-title "Rank Of Student"}} 
<h3>Rank of Students: </h3> 
<ul> 
    {{#each @model as |party|}} 
        <li>{{party}}</li> 
      {{/each}} 
</ul> 
<br /><br /> 
<div> 
    <label>Enter Item: </label> 
      {{input value=this.item}} 
</div> 
<div> 
    <label>Enter Index: </label> 
      {{input value=this.idx}} 
</div> 
<div> 
    <input 
        type="button"
        id="insert-item"
        value="Insert Item"
        {{action "insertItem" this.item this.idx}} 
      /> 
</div> 
<br /><br /> 
<div> 
    <label>Enter Item: </label> 
      {{input value=this.item}} 
</div> 
<div> 
    <input 
        type="button"
        id="first-index-item"
        value="Show Rank"
        {{action "getRank" this.item}} 
      /> 
</div> 
{{outlet}}